The present invention relates to spatial compounding. Steered spatial compounding is used in clinical environments. One component frame of data is acquired by scanning along scan lines at one angle or pattern relative to a transducer. A second component frame of data is acquired by scanning along scan lines at a different angle or pattern. Each of the frames of data represents an overlapping region of a patient. The frames of detected data are compounded together and displayed as an image.
Steered spatial compounding increases the information content of ultrasound images and reduces speckle noise in ultrasound. Compounding component frames of data associated with different scan angles may reduce speckle and may produce a more continuous border in specular targets, such as muscle layers, ductal structures, and boundaries between different tissue types.
To compound, the steered ultrasound images are averaged. Averaging performs well for speckle variance reduction, but is not best suited for preserving the angled specular targets. For specular targets, the target is best matched to the component frame steered perpendicular to the target and not other component frames. Other components steered differently may not pick up the target as well, or may miss the target all together. Averaging all the component frames may diminish the level of such matched structures.
Non-linear compounding component frames, such as maximum compounding, may preserve matched structures. However, maximum compounding provides poor speckle reduction and is ridden with a host of other problems, such as motion artifacts and increased clutter noise.